package day_2022_1_to_2.exam;

import java.util.*;

public class Exam1_2{
    public static void main(String[] args){
        Scanner scanner=new Scanner(System.in);

        while(scanner.hasNext()){
            String s=scanner.next();

            StringBuilder sb=new StringBuilder();
            Set<Character> set =new HashSet();
            for(int i=0;i<s.length();i++){
                char a=s.charAt(i);
                if(set.add(a)){
                    sb.append(a);
                }
            }
            System.out.println(sb.toString());
        }
    }
}
